Traditionally, sword blades have a cross section with a shape like a circumflex accent, as represented in FIG. 1, and the dimensions of the cross section diminish from the tang to the tip of the blade.
When this circumflex accent section is examined in regard to the strength of the materials, and relative to a plane x'-x comprising the neutral axis and separating part 2 of the blade working under extension, i.e., the wings, from the part working under compression, i.e., rib 3, it is found that the surface of the former, i.e. part 2, is greater than that of the latter, i.e. rib 3, which leads to different moments of inertia. It is also found that a "neutral zone" shown hatched in FIG. 1, i.e., the less stressed zone, comprises much material uselessly adding to rhe weight of the blade.
Another drawback of this circumflex accent cross section is the presence at the ends of wings 2 of the edges 4 which undergo the highest tension stresses and thus, when the metal reaches a high level of fatigue, favor the start of cracks which can start the crosswise breaking of the blade.
Finally, a very considerable economic drawback is involved, since the circumflex accent section combined with the variations in dimensions in the various cross sections require the blade to be made by hand, because of the absence of any reference surface allowing mechanization of its production.